1. Field of the Invention
The present invention relates to an optical lens, a compound lens and a method for producing the same, as well as a cemented lens and a method for producing the same.
2. Description of the Background Art
As an optical device becomes more sophisticated in functionality, recently, various lenses have been required as a lens for use in an optical system of such an optical device (refer to Japanese Patent Laying Open Nos. 2002-144203, 07-117143, 2002-286987 and 2005-062432). In order to fill the need, a compound lens has been used as the lens. The compound lens has a configuration that a certain lens is cemented to a matrix lens. For example, the compound lens is an aspherical lens having a configuration that a resin lens is cemented to a surface of a spherical lens.
FIG. 26 is a schematic sectional view showing a configuration of a conventional compound lens. With reference to FIG. 26, the compound lens includes a matrix lens 101 and a resin lens 102. Matrix lens 101 is, for example, a small-diameter lens having a thin outer peripheral edge. Matrix lens 101 includes a lens effective portion (an optical functional portion), a flange portion 101b and a chamfered portion 101c. 
The lens effective portion has a lens face 101a1 formed on its front side and a lens face 101a2 formed on its rear side. Flange portion 101b is formed so as to extend from an outer periphery of the lens effective portion. Chamfered portion 110c is formed on an outer periphery end of flange portion 101b. 
Resin lens 102 is cemented to lens face 101a2.
If chamfered portion 101c is formed at the outer peripheral edge of matrix lens 101, conventionally, there arises a problem that matrix lens 101 becomes deformed or chipped due to the thin outer peripheral edge.
In addition, when matrix lens 101 is produced by injection molding, an axis A102 of chamfered portion 101c is misaligned with an axis A101 of the lens effective portion. Hereinafter, description will be given of this drawback.
FIG. 27 is a schematic sectional view showing a configuration of a die used for producing matrix lens 101 by injection molding. With reference to FIG. 27, die 110 for injection molding includes a movable die 111, a fixed die 112, an insertion die 113 and an insertion die 114. A portion in the vicinity of an outer peripheral end of matrix lens 101 is molded by movable die 111 and fixed die 112 while the lens effective portion of matrix lens 101 is molded by insertion die 113 and insertion die 114.
The lens effective portion requires high accuracy. Therefore, a die used for producing the lens effective portion can be readily replaced with new one even when becoming deformed. In addition, insertion die 113 and insertion die 114 are separated from movable die 111 and fixed die 112, respectively, so as to facilitate replacement of insertion die 113 or 114.
However, insertion die 113 and insertion die 114 are separated from movable die 111 and fixed die 112, respectively, so that a clearance is created between insertion die 113 and movable die 111 and between insertion die 114 and fixed die 112. This clearance causes a disadvantage that insertion die 113 is displaced with respect to movable die 111 and insertion die 114 is displaced with respect to fixed die 112. In other words, insertion die 113 and insertion die 114 each used for molding the lens effective portion are displaced with respect to movable die 111 and fixed die 112 each used for molding the portion in the vicinity of chamfered portion 101c. As shown in FIG. 26, consequently, axis A102 of chamfered portion 101c is misaligned with axis Al01 of the lens effective portion. This axial misalignment causes a problem of transmission eccentricity.